Paul and Anne Ehrlich, Stanford University professors and population control advocates, don’t suffer fools gladly, as this frank discussion with them makes clear. As in their new Island Press book, Betrayal of Science and Reason, the Ehrlichs rely on hard scientific data, not rosy speculation and optimistic fantasy. They have been the country’s best-known population authorities for 30 years, since Paul Ehrlich published The Population Bomb, which argued forcefully that the planet was positioning itself for catastrophic human overcrowding, food shortages and mass starvation.

It was while doing field study on butterflies, reef fish and birds in the 1950s that the Ehrlichs first began to think about human population impact on a rapidly disappearing ecosystem. “Around the world,” they write in Betrayal, “we have watched humanity consuming its natural capital and degrading its own life-support systems. Virtually everywhere—be it the Conoros Islands or California, Dehli or Detroit, Antarctica or Alaska, Fiji or Florence, Tanzania or Tokyo, Australia or the Amazon, Beijing or Bora Bora—we’ve seen the results of gradually building pressures caused by increasing human numbers, overconsumption, and the use of environmentally damaging technologies and practices.”

The Ehrlichs have their critics, who point out that the worst of their doomsday predictions haven’t come to pass, but the weight of scientific evidence clearly supports their point of view—that humanity has only briefly postponed a catastrophic collision with the consequences of runaway population growth.

E: It’s now been almost 30 years since your book The Population Bomb was first published. It had enormous impact on many people who probably had not thought much about population issues before, and I think it ultimately led to a downsizing of the American family. But now you would say that Americans need a second waking up regarding population?

PAUL EHRLICH: Yes, population has become more a part of the standard discourse, but one of the things people still don’t understand is how big a connection there is between environmental problems and population size. There is a lot of concern about immigration, which is basically people flowing up a gradient of wealth, but there is almost no concern about consumption control in the United States. We have a dual problem: the third-largest population in the world and this incredibly high level of per-capita consumption, serviced very often by sloppy technologies. I’m afraid that most Americans who are aware of population problems tend to think of them in terms of poor countries.

Do you think of population as a sheer numbers problem? Is there a definitive carrying capacity of the Earth?

PAUL EHRLICH: The carrying capacity of the Earth depends on the behavior of the individuals. At current behavior we’re clearly above the carrying capacity because we’re reducing the capacity of the planet to support people in the future. Now that doesn’t mean that, in theory, if you worked out a system by which everyone was vegetarian and nobody went anywhere, you might be able to permanently support something like the present population—although few scientists who look at all the factors think that would be possible. By almost any standard, we are beyond carrying capacity now; but that doesn’t mean we can’t still go beyond that capacity for some time.

ANNE EHRLICH: We’re well past carrying capacity now, but a lot depends on what kind of lifestyle people are living and what kind of technologies we’ll have. There’s always the possibility that new technologies will support more people, but you can’t put your money on them before they show up. The Green Revolution [which spread fertilizer technology to the Third World in the 1960s] created a small miracle in doubling and tripling small crops, but there’s no reason to think that will be repeated. There are biological limits to what you can get in terms of crop yields.

Your most recent book, The Stork and the Plow, takes a rather vivid look at the environmental degradation we’ve experienced in the last couple of decades. Do you think that’s a major factor in carrying capacity? I know that Lester Brown of Worldwatch Institute raised a big furor when he wrote that China may not be able to feed itself in a few years.

ANNE EHRLICH: Lester Brown is right to focus on China, because no other country has a population of one billion and an economic growth rate of 10 percent a year. India is almost as large [in population] but its economy is growing at a much smaller rate. No one could foresee an increase in demand there that would parallel China.

PAUL EHRLICH: We’re not able to support the present population on income from our natural capital; we’re only doing it by exhausting our capital. That’s a one-way street. In other words, we are getting rid of deep, rich agricultural soils through erosion, by creating pavement, and we are getting rid of our fossil ground waters by overpumping them, by paving over recharge areas, by permanently poisoning them with industrial effluents. So we’re running into severe water constraints, and water is a non-substitutable resource in most uses. We’re also getting rid of biodiversity. I think most knowledgeable scientists believe we’ve now launched the biggest extinction episode since the one that wiped out the dinosaurs about 95 million years ago.

I believe anthropologist Richard Leakey calls it the “sixth extinction”?

PAUL EHRLICH: There have been a series of very large extinction episodes through geologic times, and unless things change very rapidly, this one will match the earlier ones. Of course, there were no human beings when the earlier ones were going on. People do not seem to understand that their fates are imminently intertwined with the other organisms of the planet. That is, they are working parts of the life support system, the eco-systems that supply our economy with absolutely irreplaceable services. In other words, if we lose most biodiversity, we will also lose our industrial civilization.

What do you say to the people Leakey calls “the anti-alarmists,” who say that a lot of the really horrible things population critics talk about haven’t happened, that species are always dying out?

PAUL EHRLICH: The one resource that we will never run out of is imbeciles. The new book Anne and I wrote basically takes on all of the arguments of the “don’t-worry, the-environment-is-in-great-shape, all-we-need-is-unconstrained-capitalism-and-everything-will-be-fine crowd,” and we take the arguments one after another and present the scientific community’s consensus on it. But it’s like creationism, you just can’t put some of these things down. There’s just an anti-intellectual, anti-science trend that is very serious in the United States, fed by idiots who just keep publishing this nonsense.You may have seen Gregg Easterbrook’s A Moment on the Earth; it’s got hundreds of serious scientific errors.

On population in particular? How is it wrong?

PAUL EHRLICH:

Easterbrook says that if you travel east from San Francisco, you quickly get into areas that have “barely known” disturbance from human beings. Now, moving east from San Francisco you go through the polluted San Francisco Bay, which has had virtually all of its wetlands destroyed; then through the polluted and developed East Bay Foothills; then into the solid agricultural Central Valley; then into the over-grazed, logged and no-top-predators-left Sierras; then into the over-grazed and full-of-exotic-plants Great Basin. If you go all the way around the world east from San Francisco you won’t find any area that hasn’t seen some major intrusion from human beings, and most of it is significant. The book is very popular, but it’s just dead wrong from one end to the other.

A lot of people are looking ahead to the coming age of environmental goodness or something. Well fine, but unfortunately scientists are charged with presenting their best diagnosis of the situation, and they’re not necessarily right. I make mistakes, all of my colleagues have made mistakes, but one of the things that we’re forced to do is get our stuff carefully reviewed by our colleagues before we publish it so we maintain our scientific reputations. You’re not going to get the credibility of the scientific community unless you have your stuff reviewed, unless you avoid childish errors.

But some of this pseudo science is just amazing. [Ehrlich arch-nemesis] Professor Julian Simon says in the 1994 book Scarcity or Abundance that we now have in our minds and libraries enough information to keep the human population growing for…guess how many years.

Thirty? Fifty?

PAUL EHRLICH: You’re a little low. Seven billion years. Well, I did a little calculation. The world population is currently doubling about every 40 years. But if you give Simon a break and calculate it at a millionth of the current rate, that is, doubling every 40 million years, for seven billion years, there would be more people than there are electrons in the universe. I mean, this is the sort of crap they put out and yet these people are taken seriously. If I believed something like that, they’d throw me out of the National Academy of Science, I’d lose my tenure at Stanford, my colleagues would laugh at me wherever I went.

In E, we have published ads from a group called Negative Population Growth (NPG) promoting immigrations curbs. Some of our readers wrote in to say the ads were racist, and that what groups like that really want is to keep out Third World people or people of color.

PAUL EHRLICH: We do live in a racist society, but one can’t say that all people who are opposed to immigration are opposed for racist reasons. I think some of them are. The facts of the case are fairly simple. Immigration to the United States is a disaster for the entire world, because immigrants take on the characteristics of Americans and become super consumers and add to the most over-populated, environmentally destroying country in the world. What we should have, and NPG is exactly right, is a birth-plus-immigrants rate that is lower than our death-plus-immigrants rate. We should have slightly fewer people moving into the population than are moving out, and keep it that way for a long time until we can get down, maybe in a century, to a sustainable population.

ANNE EHRLICH: I think it’s perfectly reasonable to be tough on illegal immigrants, with stricter border controls and other measures. And beyond that, our quotas for legal immigration are much too high; they should be cut back by a quarter, though I’d prefer not to commit to an absolute number. We have the fastest-growing population of the developed countries, over one percent a year when you add together one million legal immigrants, 2.5 million babies born and continuing illegal immigration.

I was wondering how important you saw the role of religion as a damper in preventing population control. You wrote in “The Stork and the Plow” that President Reagan and the Pope had formed something of an unholy alliance to both keep down family planning funding and to stop the spread of abortion services.

PAUL EHRLICH: There is a very big difference between religion, which I think is very helpful to a lot of people and in most cases does not affect reproductive behavior at all, and the political actions of the Pope and the Catholic hierarchy. If Paul Ehrlich tells people to have fewer babies, they don’t necessarily listen. If the Pope tells them to have more babies, they don’t necessarily listen either, as is evidenced by the fact that the average family size in Italy is 1.2 children, the lowest in the world. There is no Catholic problem in the population issue; there is a problem of the Pope making it much more difficult for governments to provide contraceptive services.

Could you make some projections of population, what it would be in the year 2025 or 2050?

PAUL EHRLICH: Projections show something in the vicinity of eight to 12 billion by the middle of the next century. All the assumptions are that we won’t see a significant rise in death rates and in birth rates. The median assumptions would lead you to something like 10 or 11, assuming a continuing decline in birth rates. We’ll be very lucky in some ways to get to eight or nine billion without having a bad die off, and it’s going to rely very heavily on the effects of widespread land use changes; how bad the climate changes induced by global warming will be, and other factors. We’re running a vast experiment on ourselves and taking out no significant insurance against destroying our life-support systems.

You actually have some optimistic passages in The Stork and the Plow. You talked to parents in India who, 20 years ago, would have had four or five kids, but now only have one or two.

PAUL EHRLICH: In the last 20 years, we’ve seen very clearly that one way to get birth rates down is to empower women, particularly to make them literate. The state of Kerala in India has a tradition of women being empowered and literate, and their fertility rate is lower than that of the United States now. Unfortunately, the resources are not being made available in many places that would help get that job done, due in no small part to former President Ronald Reagan and some of the meatballs in the Congress at the present time.

ANNE EHRLICH: Study after study shows that the more autonomy women have, the more likely they will be to accept birth control, limit families and keep them healthy. When women have decision-making power, that’s what they do.

Are you at all hopeful that what you saw in India will snowball and counteract the rapid population growth that you’d see happening otherwise?

PAUL EHRLICH: We are getting some progress in that area, it’s just not fast enough. What I would hope for is that people would realize that their basic security is environmental security, that there are just too many people in the world, all trying to consume much too much using very sloppy technologies, and that something will finally have to be done about that.

ANNE EHRLICH: I’m not necessarily pessimistic. World population is now growing at 1.5 percent a year

, where 30 years ago it was over two percent. Some of the higher population projections are really scary, but some of the lower ones are also possible and we should shoot for them.

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